Maize chloroplast genes ndhD, ndhE, and psaC. Sequences, transcripts and transcript pools

Area of Science:

• Plant Molecular Biology
• Genetics
• Biochemistry

Background:

• Plastid genomes contain essential genes for photosynthesis and respiration.
• NADH dehydrogenase (ndh) genes are involved in plant respiration and have been identified in various species.
• Photosystem I (PSI) protein psaC is crucial for photosynthetic electron transport.

Purpose of the Study:

• To determine the nucleotide and amino acid sequences of three genes in the maize plastid genome.
• To investigate the homology, transcription, and regulation of these maize plastid genes.

Main Methods:

• Nucleotide sequencing of maize plastid DNA.
• Analysis of gene homology and polypeptide sizes.
• RNA analysis to determine transcription units and expression levels under different light conditions.

Main Results:

• Identified and sequenced three maize plastid genes: ndhD, ndhE, and psaC.
• ndhD and ndhE show homology to respiratory NADH dehydrogenase subunits.
• ndhD and psaC are cotranscribed into a 2.1 kb RNA, with expression increasing threefold upon illumination of dark-grown seedlings; ndhE is independently transcribed.

Conclusions:

• The maize plastid genome encodes subunits homologous to respiratory NADH dehydrogenase.
• The psaC and ndhD genes form a cotranscribed unit regulated by light.
• This study provides insights into the genetic organization and regulation of maize plastid genes involved in respiration and photosynthesis.